Are Solar Mats usable on a yacht?

[s/v Jedi]

Originally Posted by coopec43

Aren't they saying some rays will hit the top layer of the panel directly from the sun but other rays will miss the panel, hit the "ground albedo" and be reflected onto the bottom (back) layer of the solar panel?

We were talking about a panel facing the sun or at a different angle. When you tilt the panel away from facing the sun, you simply reduce the surface area catching irradiation and the output goes down accordingly.

[wholybee]

Originally Posted by nuku34

Re mounting panels on the lifelines: IMHO not a good idea if you plan to go anywhere with waves over a 1m high. A breaking wave has tremendous force and will trash the panels and bend the stanchions. Most neophyte sailors have no idea of the damage the sea can do. Sooner or later you WILL experience a breaking wave on the beam.



Mounting the panels on an arch or on the top of the dodger is much better.


An alternative is the setup on my Joshua type 40ft ketch: we mounted narrow long glass solar panels with custom made alloy frames between the masts and the cap shrouds about 2m off the deck; a person could walk under them. So 4 panels.
The mast side of the panels mounted and pivoted on a bolt that went through the mast and stuck out about 70mm on each side. The bolt went through the frame a bit forward of the mid point. The cap shroud ends had custom mounts made from SS bulldog clips.The panels could be rotated to any angle. We generally kept them horizontal when beating to reduce windage, but at anchor or reaching or running we would adjust the angle during the day.
These 4 panels went across the Drake Passage to Antarctica, through the Magellan Straits, and through a category 9 tropical storm in the Coral Sea with NO damage.
"Sundowner" is a cutter ketch with 3 sizes of high clewed jibs on the forestay. The clews of all the jibs are higher than the panels so there is no interference between clew and panel when tacking.
Its a simple and elegant solution well suited to ketches 40ft or over.
Attached are 3 photos. 2 of Sundowner which shows the placement of the panels. The 3rd is her sister ship after doing a backward pitch pole off a 40ft wave in the Med (not the Southern Ocean).

I circumnavigated with solar panels on the lifelines secured by the largest plastic zipties i could find. They endured all kinds of abuse. Breaking waves hitting them and filling the cockpit, 50 kt winds, waves hitting them on the side, knockdowns etc. I expected that I would lose them at some point, but that by saving thousands of dollars for some more appropriate structure it was smarter to just plan on replacing a few hundred dollars worth of panels. But, after 30,000 miles, I have to reject any claim that securing to the lifelines isn't good enough.

[nuku34]

Fair enough Warren,

How big are the panels and what is the freeboard of your Morgan?

[akopac]

I have a a 38 foot ketch and am solar independent with 400W of solar. I have swing out davits on the stern and use them even underway off shore in normal conditions. We have used this setup for over 20 years with no issues. I included pics here so you can see how they are setup.

[fxykty]

Originally Posted by akopac

I have a a 38 foot ketch and am solar independent with 400W of solar. I have swing out davits on the stern and use them even underway off shore in normal conditions. We have used this setup for over 20 years with no issues. I included pics here so you can see how they are setup.

Awesome solution, thanks for sharing.

How are the swinging davits attached to the boat? There would be a lot of load on the deck fitting.

[Eder]

I just bought some of these

[shimari]

Originally Posted by Eder

I just bought some of these

Let us know how they work out. I’ve been considering those for the top of our Bimini.

[Rohan]

Originally Posted by coopec43

Helen is a ketch and therefore finding places for solar panels can be difficult. Would a 380W solar mat attached to the stanchions/lifelines be a proposition?

https://www.batterymate.com.au/produ...a&gad_source=1

Assuming this works, why is no one else mentioning that 380 watts solar for $160 is an insanely good deal? Especially when it's foldable.

I paid $200 for this AIPER 100W foldable solar panel, although I like it a lot. It's durable, folds up into a nice sized case, and easy to deploy, easy to angle towards the sun. I already have 350W installed solar, but I use the portable panel when anchored to add more charging for smaller devices like cellphones, tablets, laptop, etc. It's small enough that wind is not a problem unless its super strong. Heavy wind against a 380W panel that is six feet across attached to the lifelines or rigging might be a problem though.

[wholybee]

Originally Posted by nuku34

Fair enough Warren,

How big are the panels and what is the freeboard of your Morgan?

The panels are 100W each, and I have 4 of them. I'd have to measure the freeboard. It isn't super tall. I've actually had the panels partially submerged a few times when overpowered and gusts come up. I try to avoid that. In the worst conditions I tie them down instead of sticking out.

[akopac]

Originally Posted by fxykty

Awesome solution, thanks for sharing.

How are the swinging davits attached to the boat? There would be a lot of load on the deck fitting.

I had the upper lifelines replaced with stainless from the gates back to the rear pulpit. The davit’s are clamped on to the stations with stainless hardware the fabricater had. The fabricator used delryn for the pivot bearings. Never had a load problem or leaks from the Stanton bases.

[Pete7]

Originally Posted by s/v Jedi

We were talking about a panel facing the sun or at a different angle. When you tilt the panel away from facing the sun, you simply reduce the surface area catching irradiation and the output goes down accordingly.

Not quite, the surface area of the panel will be the same, the amount of sunlight that meets the panel is reduced.

We have a 110w Dokia folding panel. the panel has fretted over time and scratched the clear plastic surface in a couple of areas. Suggest that a piece of foam or soft material is placed inside folding panels to stop this when panels are stored below.

Akopac's swinging solution is brilliant. Need to find some old farm gates

[coopec43]

Maybe the way to go is to install bifacial solar panels instead of monofacial panels. (Bi-facial solar panels absorb sun's rays on one side of the panel and reflected rays on the other)

If I install two bifacial panels in series (24V) on top of the push-pit and mirrors on the deck reflecting sun's rays on to the back of the solar panel that would be highly efficient even in a rough sea.

https://www.custommarineproducts.com...ar-panels.html

https://www.youtube.com/watch?v=mzqjCsZKUYQ

[coopec43]

A few more links.

https://www.youtube.com/results?search_query=bifacial+solar+panels+on+boat s

[s/v Jedi]

Originally Posted by Pete7

Not quite, the surface area of the panel will be the same, the amount of sunlight that meets the panel is reduced.

We have a 110w Dokia folding panel. the panel has fretted over time and scratched the clear plastic surface in a couple of areas. Suggest that a piece of foam or soft material is placed inside folding panels to stop this when panels are stored below.

Akopac's swinging solution is brilliant. Need to find some old farm gates

Not talking about the surface area of the panel. A child understands that doesn’t change. The surface area of the cross section perpendicular to the solar rays is reduced.

I really thought it would be easy to grasp.

[s/v Jedi]

Originally Posted by coopec43

Maybe the way to go is to install bifacial solar panels instead of monofacial panels. (Bi-facial solar panels absorb sun's rays on one side of the panel and reflected rays on the other)

If I install two bifacial panels in series (24V) on top of the push-pit and mirrors on the deck reflecting sun's rays on to the back of the solar panel that would be highly efficient even in a rough sea.

https://www.custommarineproducts.com...ar-panels.html

Except it will overheat. Search the Tech Ingredients channel on YouTube.